1. Technical Field
The present invention relates to an optically measurement device and an optically measuring method, and particularly to a multi-functioned optically measurement device for measuring a plurality of parameters of an object and a method for optically measuring a plurality of parameters of an object, the parameters may be a surface profile, a gray-level image and a full focal colorful image, and a thin-film thickness.
2. Related Art
With rapid improvement of various micro-level manufacturing technologies in the industry, there is an increasing demand on measurement of such micro-level devices. The various 3D contour measuring technologies used in the prior art can not satisfy with the general requirement any more.
In the semiconductor, flat displays, and micro-electromechanical devices and electronic package fields, since there is a crucial effect of the precision and mechanical property of the surface profile of the micro-structure surface on the product's efficacy and lifetime, the quality presented on the manufacturing process has to be monitored. Hence, there is quite a need to accurately measure the surface profile of the micro-structure, and which is typically done by some optical instruments together with some optical technologies.
How the interferometry, confocal microscopy and ellipsometry functions are performed by the white-light interferometer, microscope, and ellipsometer have been readily known by those persons skilled in the art. They may each deduce a corresponding parameter of a measured object by its optical measurement for monitoring the on-line manufactured semiconductor products.
The interferometer for surface profile measurement of the object is implemented into an optical path. There are three type of interferometers: Mirau, Linnik, and Michelson. For the Mirau and Michelson types, their reference surface is integrated into an object lens and not adjustable. On the other hand, the optical architecture of the Linnik type enables its reference optical-path and optical system to be adjustable and flexible, and which may be manual operated by the user.
A typical commercial confocal microscope may be used to obtain an on-focus whole-field image of a measured object by first vertically scanning the measured object and assembling the scanned images together with an image processing, to obtain a high frequency information for each of the pixels in the scanned image, so that a depth-of-focus gray level of each of the pixels is deduced and thus the whole-field information is secured.
To measure a thin-film thickness, the ellipsometer is generally adopted, in which a linear polarized light is first formed by polarizing a light source, and then adjusted for its phase through a compensation plate. Then, the formed light is incident onto an object having a thin film thereon and then reflected back onto a second polarization plate, an analyzer, and compensated therein. And, a detector is used to record the reflected light and analyze the associated Stokes parameter, and the amplitude and the phase of the reflected light, thereby reversely deducing a thickness information of the thin film.
However, the currently available interferometer, confocal microscope and ellipsometer each only have one single measurement function. And, so far, the efforts on these instruments have been mostly only made for enhanced precision and stability of their measurement algorithms.
In measuring a bulk dimension, a public US patent application, US2013/0033698 A1, disclosed such a method by reflecting two light beams from the front and rare surface of the measured object, detecting a spectrum of the light beams reflected from the front and rare surface of the measured object, respectively, and utilizing a processor to analyze a thickness value between the two faces.
A public US patent application, US2012/0218561 A1, disclosed a method for deducing a bulk dimension by measuring a time difference between light beams are reflected from the front surface and the film interface of the measured object by using a spectrometer or a light detector, i.e. the time difference between the time when a surface reflected light and an interface reflected light are respectively received, and then deducing the bulk dimension by using a computer.
U.S. Pat. No. 8,416,491 B2, disclosed a method capable of on-line recognizes a surface profile of a measured object by employing the confocal microscopy principle, where a series of strip structured light beams are propagating from a light source to explore a depth response curve, so as to secure a depth distribution within a measuring range of the object and thus the surface profile of the measured object may be reversely deduced.
U.S. Pat. No. 8,416,399 B2, disclosed a method for measuring the surface profile and the thickness of the measured object by using a white-light interferometry method and a reverse measurement method.
TW patent, TW096147071, disclosed a method for obtaining a three dimensional contour of a measured object by receiving R, G and B interference signal spectra by using an off-axis digital full color method, and finally calculating three colors, R, G and B, information and phases by using a computer calculation.
However, since the semiconductor industry has a trend to seek a higher integration solution for its manufacturing to achieve a reduced manufacturing time and systematic performance, to further save its manufacturing cost and simplified process flow, the currently used optical measurement devices have a need to be further reduced in its cost and processing time when parameters measurement of the measured object is considered. Moreover, the object stands some possibility of damage when it is moved for the parameters measurement Therefore, how may the optical measurement achieves in an on-line performance becomes an issue to be overcome in the micro-level industries, such as the semiconductor industry.
In view of the above prior arts, it may be known that the optical measurement instruments has a need to get more integrated, so that the efficacies of equipment cost saving, on-line measuring, rapid monitoring, reduced manufacturing time, and reduced possibility of object damage during the product manufacturing process may be achieved to facilitate industry improvement.